Hello Alcoholocaust, thank you for posting and welcome to the Unreal community.
Would you mind sharing the errors you receive when your lighting build fails?
Depending on if you are using the source build or getting the engine from the launcher, the cause of the concern could vary.
I found an older thread that discusses at length for both situations. Solutions range from rebuilding the lightmass module itself, using development editor mode in VS, and if you are using a version on UE from the launcher, you may have to check around your level for any errant meshes.
Please have a look as I found this thread most insightful.